distillation
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I would like to ask why, in the distillation process, low-boiling substances are removed first and then high-boiling substances?
Low-boiling substances, as the name implies, have a low boiling point and therefore vaporize first and escape. It’s not a matter of whether they need to be removed first or not; it’s their properties that determine that they must be removed first
Separation is carried out based on differences in volatility!
Distillation relies on the difference in boiling points for separation; the substance that comes out first is definitely the one with a lower boiling point. But what you mentioned is quite interesting – in the case of separating pure two-phase substances, who do you think separates first?~~
From an energy-saving perspective, it is better to start with low temperatures and then move to higher temperatures; there should be more material at low temperatures and less at high temperatures. If we start with high temperatures first and then move to lower ones, there will be more material at high temperatures and less at low temperatures, which isn’t a waste of energy?
It is not necessary to remove the light components first or the heavy components first. It is necessary to consider the overall process design. For the separation of the same mixture, in some cases the heavy components are removed first, while in others the light components are removed first. This takes energy consumption into account, among other things.
It depends on the specific process requirements; there is no universal answer – lower-boiling-point products should be removed first
If you have a high proportion of heavy components and the physical and chemical properties are poor, such as coking or discoloration, it’s better to remove the heavy components first; however, this is not absolute – it depends on the parameters of the specific process